Internal combustion engines, such as gasoline engines, include a crankshaft that is rotated via reciprocating operation of cylinders of the engine. The torque produced via the crankshaft is transmitted from one end of the crankshaft to the wheels of a vehicle in which the engine is installed. The other end of the crankshaft is used to drive various auxiliary machinery (e.g., accessories), such as alternators, power steering and air conditioning compressors. During engine operation, the crankshaft may experience varying levels of torsional vibration due to the sequential explosion of combustible gases in the cylinders. Torsional vibration can greatly reduce crankshaft life and cause crankshaft degradation or degradation of other engine components if the crankshaft runs at or through resonance. The vibrations can also cause noises such as a “whine” or knocking, both of which may be undesirable to a vehicle operator. In some examples, a damper (e.g., torsional vibration damper) is positioned at an end of the crankshaft (e.g., the free, accessory drive end of the crankshaft) in order to reduce these torsional vibrations. The damper may include an inner metal hub directly attached to the end of the crankshaft, one or more inertia plates, and one or more cover plates covering the inertia plates within the hub. In some examples, an additional cover, such as the metal hat-like member shown in U.S. Pat. No. 4,794,816, may be used to cover an end of the assembled damper.
However, the inventors herein have recognized potential issues with such systems and conventional crankshaft dampers. As one example, the damper alone, or additional metal covers coupled to the damper, may not sufficiently reduce noise, vibration, and harness (NVH) from the engine crankshaft, thereby resulting in component degradation and undesirable noise experienced by the vehicle operator. Further, mechanically fixing components (e.g., via bolting), such as covers, to the damper may result in an increased number of parts and thus increased component costs. Additionally, fixing components together in this way may require increased assembly time and labor costs.
In one example, the issues described above may be addressed by a system, comprising a crankshaft damper cover, the crankshaft damper comprising: a frame including a first plurality of extensions arranged around a perimeter of the frame and extending from a base of the frame in a direction of a centerline of the cover; and an inset molded around the frame and including a second plurality of extensions aligned with the first plurality of extensions. As one example, the inset may comprise a rubber or foam material and the inset may be formed as one piece with the frame. In this way, the inset may further reduce NVH from the crankshaft. As another example, the frame may comprise a material (e.g., metal) that is rigid relative to the material of the inset in order to retain a shape of the damper cover. Additionally, the damper cover may easily mate with (e.g., plug into) and couple to the crankshaft damper body via without the aid of additional mechanical fixers (such as bolts). This may reduce component costs and assembly time for the crankshaft.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
FIGS. 1-12 are shown to scale, though other relative dimensions may be used.